UC17131/2/3 UC27131/2/3 UC37131/2/3 Smart Power Switch FEATURES DESCRIPTION • 300mA Continuous Output Current The UC37131, UC37132 and UC37133 are a family of smart power switches which can drive resistive or inductive loads from the high side or low side. • Low Side or High Side Switch Configuration • 8V to 65V Operation • Overload and Short Circuit Protection • Power Interruption Protection • +6V Regulated Voltage • 2mA Quiescent Current • Programmable Overcurrent and Power Interruption Protection The UC37132 is available in 14 pin (DIP), 16 pin (SOIC), or 20 pin (CLCC) packages and can accommodate both low side (load to VCC) or high side (load to GND) configurations. The UC37131 and UC37133 are exclusively for a low side or a high side configuration respectively and both are available in an 8 pin package. Both high side and low side configurations provide high current switching with low saturation voltages which can drive resistive or inductive loads. The input to the switch is driven by a low voltage signal, typically 5V. Additionally, UC37132 features adjustable hysteresis. The output of the device can switch a load between 8V and 65V. Output current capability is 300mA continuous or 700mA peak. • 1% to 30% Programmable Input Comparator Hysteresis (on UC37132) The device also has inherent smart features that allow for programmable turn-on delay in enabling the output following startup. The same capacitor • Low and High Side Internal High that specifies the turn-on delay is also used to program a VCC power interCurrent Clamps When Driving ruption time. If VCC drops below a threshold for a time specified by this caInductive Loads pacitor, the output is turned off and a new turn-on delay will be re-triggered. Similarly, if high current persists longer than the response delay, the output driver will operate in a very low duty cycle mode to protect the IC. UC37132 BLOCK DIAGRAM VREF 6V PRE-REGULATOR 11 7 VCC 6 CSH 5 LS 4 HS 3 CSL 2 GND 6V/8mA IN INPUT COMPARATOR 13 72V Q OUT TURN-ON/OFF AND SHORT CIRCUIT PROTECTION 1/2 VREF 12 9 10 HYST LED CDEL UDG-98026 SLUS340 - APRIL 1999 UC17131/2/3 UC27131/2/3 UC37131/2/3 UC37131 BLOCK DIAGRAM VREF 6V PRE-REGULATOR 3 8 VCC 7 LS 6 CSL 5 GND 6V/8mA INPUT COMPARATOR 4 IN 72V HYST (FIXED) = 30% Q OUT TURN-ON/OFF AND SHORT CIRCUIT PROTECTION 1/2 VREF 1 2 LED CDEL UDG-98059 UC37133 BLOCK DIAGRAM VREF 6V PRE-REGULATOR 3 8 VCC 7 CSH 6 HS 5 GND 6V/8mA IN INPUT COMPARATOR 4 HYST (FIXED) = 30% 72V Q OUT TURN-ON/OFF AND SHORT CIRCUIT PROTECTION 1/2 VREF 1 2 LED CDEL UDG-98060 2 UC17131/2/3 UC27131/2/3 UC37131/2/3 CONNECTION DIAGRAMS ABSOLUTE MAXIMUM RATINGS VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65V LS – HS (Clamped by internal circuitry) . . . . . . . . . . . . . . . 78V CSH, LED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65V Output Current Continuous . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 400mA Peak . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 900mA Remaining Pin Voltages . . . . . . . . . . . . . . . . . . . . . –0.3V to 9V Storage Temperature . . . . . . . . . . . . . . . . . . . −65°C to +150°C Junction Temperature . . . . . . . . . . . . . . . . . . . –55°C to +150°C Lead Temperature (Soldering, 10 sec.) . . . . . . . . . . . . . +300°C SOIC-16 (Top View) (for UCX7132) D Package Currents are positive into, negative out of the specified terminal. Consult Packaging Section of Databook for thermal limitations and considerations of packages. PLCC-20 (Top View) (for UCX7132) L Packages N/C 1 16 N/C GND 2 15 IN CSL 3 14 HYST HS 4 13 VREF LS 5 12 CDEL CSH 6 11 LED N/C 7 10 N/C VCC 8 9 N/C N/C LS CSH HS CSL 3 2 1 N/C 4 18 N/C VCC 5 17 GND N/C 6 16 N/C N/C 7 15 N/C N/C 8 14 9 DIL-8, SOIC-8 (Top View) (for UCX7131) J, N, or D Packages 20 19 LED 1 8 VCC IN CDEL 2 7 LS HYST VREF VREF 3 6 CSL IN 4 5 GND 10 11 12 13 N/C LED CDEL DIL-14 (Top View) (for UCX7132) J, or N Packages DIL-8, SOIC-8 (Top View) (for UCX7133) J, N, or D Packages N/C 1 14 N/C GND 2 13 IN CSL 3 12 HYST LED 1 8 VCC HS 4 11 VREF CDEL 2 7 CSH LS 5 10 CDEL VREF 3 6 HS CSH 6 9 LED IN 4 5 GND VCC 7 8 N/C PRODUCT SELECTION TABLES PART NUMBER UCX7131 UCX7132 UCX7133 CONFIGURATIONS Low Side Only Low Side or High Side High Side Only PACKAGE PIN COUNT 8 14, 16, 20 8 PART NUMBER UC1713X UC2713X UC3713X 3 TEMPERATURE RANGE –55°C to +125°C –40°C to +85°C 0°C to +70°C AVAILABLE PACKAGES J, L D, N D, N UC17131/2/3 UC27131/2/3 UC37131/2/3 ELECTRICAL CHARACTERISTICS Unless otherwise specified, CDEL = 10nF, VCC = 25V, CSL = GND, CSH = LS; RCSH = 0.5Ω (Note 1); IN=0V (for OFF condition) and IN=5V (for ON condition); TA = TJ. PARAMETER TEST CONDITIONS MIN TYP MAX UNITS 25°C 5.8 6 6.2 V –55°C to 125°C 5.6 6 6.4 V Reference VREF Line Regulation VCC = 8V to 64V 10 35 mV Load Regulation 0 < IREF < 8mA 10 50 mV Short Circuit Current REF = 0V 20 35 mA 3 3.3 V 5 µA Input Comparator Turn-On Threshold Voltage 2.7 Input Bias Current VIN = 3.5V Hysteresis RHYST = GND (Internally for X31, X33) 0.775 RHYST = 96.67k for (X32) 0.9 1.025 30 V mV Output: High Side (UCX7133: CSH = LS and CSL = GND Internally; See Fig. 2a) Rise Time (Off to On) RLOAD = 250Ω to GND 30 Fall Time (On to Off) RLOAD = 250Ω to GND Output Short Circuit HS = 0.25Ω to GND 500 Voltage Clamp LS–HS 67 77 V Saturation Voltage 25°C, RLOAD = 100Ω to GND 1.2 V –40°C, RLOAD = 100Ω to GND 1.3 V –55°C, RLOAD = 100Ω to GND 1.4 V 5 µA 30 72 Leakage Current 80 V/µs 80 V/µs 900 mA Output: Low Side (UCX7131; CSH = VCC and CSL = HS Internally; See Fig. 2b) Rise Time (On to Off) RLOAD = 250Ω to VCC, RCSL = 0.5Ω 15 50 V/µs Fall Time (Off to On) RLOAD = 250Ω to VCC, RCSL = 0.5Ω 25 60 V/µs Output Short Circuit LS = 0.25Ω to VCC 500 700 900 mA Voltage Clamp LS–HS 67 72 77 V Saturation Voltage 25°C, RLOAD = 100Ω to VCC, RCSL = 0.5Ω 1.2 V –40°C, RLOAD = 100Ω to VCC, RCSL = 0.5Ω 1.3 V –55°C, RLOAD = 100Ω to VCC, RCSL = 0.5Ω 1.4 V 5 µA Leakage Current VCC Fault Section Output Turn-On Delay, tD(ON) Step VCC from 0V to 8V (See Fig. 3a) 9.5 11 13.5 ms Output Turn-Off Delay, tD(OFF) Pulse VCC from 25V to VCC Turn-Off Threshold 300 500 700 µs VCC Turn-Off Threshold Pulse VCC Low 6.5 7 7.5 V CDEL Section VCDEL_MAX 5.8 V VFAULT_H 4.9 V VFAULT_L 1.0 V 75 µs Overcurrent Fault Section (See Fig. 3c) Short Circuit Turn-Off Delay, tSC Step ILOAD: 0mA to 400mA Short Circuit Recovery Time, tROFF ILOAD = 400mA, 100µs High Side Current Threshold, ITH-H RCSH = 0.5Ω 250 325 400 mA Low Side Current Threshold, ITH-L RCSL = 0.5Ω 250 325 400 mA Overcurrent Duty Cycle RLOAD = 0.25Ω to GND 0.6 0.8 1.0 % 4 10 ms UC17131/2/3 UC27131/2/3 UC37131/2/3 ELECTRICAL CHARACTERISTICS Unless otherwise specified, CDEL = 10nF, VCC = 25V, CSL = GND, CSH = LS; RCSH = 0.5Ω (Note 1); IN=0V (for OFF condition) and IN=5V (for ON condition); TA = TJ. PARAMETER TEST CONDITIONS MIN TYP MAX UNITS 5.0 8.0 11.0 mA 1 5 µA 3 6 µs LED Output ISINK, tDOFF, tROFF VLED = 7V ILEAKAGE Overall Delay to Output ICC Output Off 2.0 2.8 mA IL = 1mA, 250mA (High Side) 2.3 3 mA IL = 1mA, 250mA (Low Side) 2.5 4 mA Note 1: All test conditions are for a high side configuration as in Fig. 2a, unless otherwise specified. PIN DESCRIPTIONS HS: (For UC37132 and UC37133) The output of the switching transistor in the high side configuration. The emitter of the output transistor is the HS pin which is connected to the load. For the UC37132, the HS pin must be tied to the CSL pin in a low side application. CDEL: A capacitor connected to this pin is used to program both VCC pulse interruption time and power turn-on delay. The capacitor discharge time corresponds to VCC interruption and the charge time to VCC turn-on delay. The ratio between turn-on delay and turn-off delay will be fixed based on internal charge and discharge currents and voltage thresholds. HYST: (For UC37132) The pin used to program the input comparator hysteresis by connecting a resistor to ground. The hysteresis defaults to 30% with HYST grounded (internally for UC37131 and UC37133). The same fault circuitry and capacitor is used for short circuit and overload protection. If an overcurrent or short circuit is detected, the capacitor starts charging and turns off the output if the condition persists at the end of its charge time. The output will then operate in a low-duty cycle mode to protect the IC. After short circuit recovery, the output will be reactivated in order to check if the short circuit was removed. If the overcurrent persists the chip will continue in this pulsing mode. V HYST = 3000 (3330 + R HYST ) IN: The input to the comparator that detects when the output transistor should be turned on. The input threshold is 3.0V (1/2 VREF) and the input voltage range is 0V to VREF. CSH: (For UC37132 and UC37133) This high side current sense pin is used to program the current limit for high side applications by connecting a resistor between VCC and CSH. An over load current is detected when the voltage drop between VCC and CSH exceeds 150mV. For the UC37132, in a high side application, the CSH pin must be tied to the LS pin; in a low side application, the CSH pin must be tied to VCC LED: Open collector output intended to drive an LED. This pin is driven low whenever the output is turned off and is externally pulled high when the output is turned on (see Fig. 3b and 3c). LS: (For UC37131 and UC37132) The output of the switching transistor in the low side configuration. The collector of the output transistor is the LS pin which is connected to the load. For the UC37132, the LS pin must be tied to the CSH pin in a high side application. CSL: (For UC37131 and UC37132) This low side current sense pin is used to program the current limit for low side applications by connecting a resistor between CSL and GND. An over load current is detected when the voltage drop between CSL and GND exceeds 150mV. For the UC37132, in a high side application, the CSL pin must be tied to GND; in a low side application, the CSL pin must be tied to the HS pin. VREF: The 6V regulated reference capable of supplying up to 8mA. The recommended decoupling capacitor is 1nF. VCC: The supply voltage for the chip. Decouple this pin with a good quality ceramic capacitor to ground. GND: The reference point for the internal reference, all thresholds, and the return for the remainder of the device. 5 UC17131/2/3 UC27131/2/3 UC37131/2/3 DESCRIPTION OF OPERATION Reference current of approximately 4µA. If the power stays off longer than this time, then a power up delay will be initialized once power is resumed. This delay is the time it takes for CDEL to charge from 0V to VFAULT_H of 4.9V. The UC37131/2/3 family of devices features a 6V bandgap reference that is used to bias on-chip logic. Although the 6V reference is not trimmed, this bandgap reference provides less than 200ppm/°C. It is also used to generate the on-chip 3V input comparator threshold and is needed for the programmable hysteresis. The on-chip reference has 8mA maximum current sourcing capacity that is designed to power up external circuitry. The overcurrent fault normal operation consists of the chip staying off until CDEL fully recharges to VFAULT_H of 4.9V. This is tR(OFF). Once CDEL reaches 4.9V, the driver will turn back on. If the overcurrent fault is still present, the chip will operate in a very low duty cycle (approximately 0.7%) based on the discharge (driver on) and charge time (driver off) of the CDEL capacitor. This overcurrent timing makes the chip act "smart" by allowing very high currents needed to drive large capacitive loads without setting off an overcurrent fault. Input Comparator The input comparator is a high gain comparator with hysteresis that fully switches with either a small signal (30mV, minimum for 1% hysteresis) or a logic signal (0 to 6V max). Only a 5mV overdrive of the 3V threshold is needed to switch the driver. The overcurrent and current limit thresholds are programmed with the resistor RCSH from CSH to VCC (high side) or RCSL from CSL to GND (low side). For example, a 150mV (ILOAD • RCSH) threshold will set the high side overcurrent fault threshold. An overall short circuit protection threshold is set at 300mV. Therefore, the recommended RCSH of 0.5Ω will result in the 600mA short circuit. By changing the RCSH value the user can optimally set the overcurrent and short circuit current limits. The hysteresis is set to 30% on the UC37131 and UC37133. (This is 30% of 3V equating to 0.9V of hysteresis.) On the UC37132 it is programmable from 1% to 30%. Fault Logic The output of the comparator is logic ANDed with the output of the fault logic. If a fault, either a power interrupt or an overcurrent condition, persists longer than it takes for the CDEL to discharge from its VCDEL_MAX level of 5.8V to its VFAULT_L of 1.3V, the fault protection block will output a logic 0 to the NAND gate and turn off the output driver. If the fault goes away prior to CDEL being discharged to 1.3V, the chip will resume normal operation without going through a turn-on delay. Output Driver Once the turn-on signal is gated through from the input comparator, the output transistor is turned on. The output drive transistor is a composite PNP, NPN structure. This is a specially designed structure that keeps all the drive current needed for the load to be sourced through the LS pin. This keeps the overall power dissipation to less than 4mA independent of the load. The power interrupt normal operation consists of the chip turning the driver immediately back on if the interrupt goes away prior to CDEL reaching its lower threshold as described above. The CDEL capacitor is chosen based upon the maximum power interrupt time (tINT) allowed without the output experiencing a turn-on delay. This interrupt time must be less than tD(OFF) where tD(OFF) is equal to the time it takes the CDEL capacitor to discharge from VCDEL_MAX (5.8V) to VFAULT_L (1.3V) with a discharge current of approximately 94µA. If the power stays off only as long as tD(OFF), the minimum power up delay will be equal to the time it takes to charge CDEL from VFAULT_L (1.3V) to VFAULT_H (4.9V) with a charge The output driver also has a 72V zener diode wired between its base and collector. This allows the output to swing and clamp to 72V above ground when discharging an inductive load in a low side application. The inductive zener clamp can discharge the 250mA to 400mA full load current. This consequently allows the LS pin to safely swing above VCC. Similarly, the 72V zener diode will allow the HS pin to safely swing and clamp 72V below LS/VCC when discharging an inductive load in a high side application. This 72V zener diode simplifies the user application by eliminating the need for external clamp diodes. 6 UC17131/2/3 UC27131/2/3 UC37131/2/3 APPLICATION INFORMATION ence an indeterminate state during this interruption, but resume normal operation when VCC power returns to normal. Choosing The CDEL Capacitor The maximum amount of time that VCC power can be interrupted and not require the outputs to go through a turn-on delay cycle is user programmable by the CDEL capacitor value. While VCC is interrupted, the outputs will be in an indeterminate state and they may turn off during this interval, tINT. However, as long as the programmed interruption time is not exceeded, the outputs will immediately turn back on with the return of VCC. If the VCC power is interrupted for a time equal to or longer than tD(OFF) then the following relationships apply. As the CDEL capacitor discharges past the VFAULT_L threshold, the output is fully disabled and must cycle through a power up delay equal to tD(ON). The charge current for the CDEL capacitor is equal to 4µA. The outputs will turn on when the CDEL capacitor charges up to the VFAULT_H threshold of 4.9V. The minimum turn-on delay the outputs will experience will occur if tINT is exactly equal to the tD(OFF) time and the CDEL capacitor has only discharged to VFAULT_L. This would be the minimum turn-on delay time and is calculated with the following equation: For example: t INT ≈ 500µs (User specified) CDEL is selected such that the time it takes for this capacitor to discharge from VCDEL_MAX (5.8V) to VFAULT_L (1.3V) with a discharge current of 94µA is just greater than this tINT. This time is referred to as tD(OFF) in Fig. 3b. CDEL = t D (ON ) I DISCHARGE • t D (OFF ) VCDEL _MAX − V FAULT _L CDEL • V FAULT _L − V FAULT _H ICHARGE Using the 10nF CDEL capacitor, for example, the minimum turn-on delay calculates to 9ms. If the CDEL capacitor discharges completely to zero, then the 10nF CDEL capacitor would cause a turn-on delay of 12.25ms. The outputs would be off for this amount of time after VCC power is restored. The total amount of time the outputs could be disabled is equal to the tINT time, which may include the indeterminate time of tD(OFF), and the tD(ON) time, as shown in Fig. 3b. If tD(OFF) is set equal to tINT, which the user has selected to be 500µs, the minimum CDEL capacitor is calculated: CDEL = min = 94µA • 500µs 58 . V − 13 .V For this application, the CDEL capacitor value calculates to 10.4nF. By using a 10nF capacitor on CDEL, VCC can be interrupted for up to 478µs and the outputs will experiVREF 6V PRE-REGULATOR 11 7 VCC ICC CREF 6 +L RCSH CSH POWER SUPPLY LS 5 IN INPUT COMPARATOR 13 72V CCC VREF Q OUT GND HS 4 1/2 VREF TURN-ON/OFF AND SHORT CIRCUIT PROTECTION OUT LOAD CSL 3 2 GND –L IGND 12 9 HYST LED R 10 CDEL CCDEL HYST UDG-98027 Figure 2a. High side application. 7 UC17131/2/3 UC27131/2/3 UC37131/2/3 APPLICATION INFORMATION (cont.) VREF VCC 6V PRE-REGULATOR 11 7 +L ICC CREF 6 CSH CCC LOAD LS 5 IN INPUT COMPARATOR 13 OUT 72V POWER SUPPLY VREF Q OUT GND HS 4 TURN-ON/OFF AND SHORT CIRCUIT PROTECTION 1/2 VREF CSL 3 RCSL 2 GND –L IGND 12 HYST 9 10 LED CDEL CCDEL RHYST UDG-98028 Figure 2b. Low side application. tINT VCC t VCDEL_MAX = 5.8V VCDEL VFAULT_H VFAULT_H = 4.9V t OUTPUT DRIVER tD(ON) DISABLED ENABLED ENABLED t INDETERMINATE STATE UDG-98029 Figure 3a. Power interrupt ignore operation, high side configuration, VIN = 5VDC. 8 UC17131/2/3 UC27131/2/3 UC37131/2/3 APPLICATION INFORMATION (cont.) tINT VCC t VCDEL_MAX = 5.8V VCDEL VFAULT_L = 1.0V VFAULT_H VFAULT_H = 4.9V t tD(OFF) tD(ON) tD(ON) OUTPUT DRIVER DISABLED DISABLED ENABLED ENABLED t t LED INDETERMINATE STATE UDG-98030 Figure 3b. Power interrupt fault operation, high side configuration, VIN = 5VDC. ILOAD t 4.9V VCDEL t tSC OUTPUT DRIVER t tR(OFF) LED t UDG-98031 Figure 3c. Overcurrent fault operation. 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